Types of Cysts on Dogs: Complete Guide for Owners

Cysts are among the most common lumps or bumps found on dogs. While many cysts are benign and harmless, some require medical attention. Understanding the various types of cysts, their causes, and the best management practices is essential for all dog owners who want to ensure their pet’s health and comfort.

What Is a Cyst?

A cyst is a closed sac-like structure that can form in or under the skin, or inside the body, typically filled with fluid, semi-solid, or solid materials like keratin or sebum. Most cysts are benign (non-cancerous), but distinguishing between a harmless cyst and other types of lumps is crucial for timely veterinary care .

Are Cysts On Dogs Dangerous?

Most cysts on dogs are benign and do not pose serious health risks. However, some cysts can become infected, rupture, or, in rare cases, indicate an underlying health problem. Owners should monitor any lumps—documenting their appearance, size, and changes—and seek veterinary advice if there is any doubt.

• Benign cysts: Usually slow-growing, painless, and non-contagious .
• Infected cysts: May appear red, swollen, leak pus, or cause discomfort.
• Malignant tumors: Uncommon, but some aggressive tumors (e.g., mast cell tumors) may mimic cysts .

Common Types of Cysts in Dogs

Canine cysts can be classified by their origin, composition, and location. Below is an overview of the primary types, including their features and common locations.

True Cysts

True cysts are lined with an epithelial membrane that produces fluid, causing the cyst to grow. They usually arise in glands, especially sweat glands, contributing to their fluid content. True cysts are most often benign, but removal may be necessary if they grow large or recur .

• Appearance: Generally round, slightly translucent or bluish, occasionally painful.
• Treatment: May require surgical removal, especially if recurring; complete removal of the lining is crucial to prevent recurrence.

False Cysts

Unlike true cysts, false cysts have no epithelial lining and result from trauma or injury that causes tissue death and fluid accumulation. Most false cysts resolve as the tissue heals naturally .

• Appearance: Soft, fluid-filled, generally dark; may develop after a bruise or injury.
• Treatment: Observation; usually resolve on their own. Veterinary intervention if persistent, large, or painful.

Sebaceous Cysts

Sebaceous cysts form when oil glands (sebaceous glands) become blocked, leading to a buildup of sebum (an oily substance). They are among the most common cysts seen in dogs and can occur anywhere hair follicles are present.

• Appearance: Smooth, round, and sometimes bluish or white. Can exude thick, cheese-like material if ruptured or squeezed.
• Treatment: Monitor unless infected or persistently problematic. Do not attempt to squeeze or pop a sebaceous cyst at home due to risk of infection. Veterinary removal if recurrent or bothersome .

Follicular (Epidermoid) Cysts

These cysts, also known as epidermoid cysts, form as a result of inflammation or blockage of hair follicles. They frequently appear on the face, neck, trunk, and sometimes legs. Their contents are usually composed of keratin, a protein found in hair and skin cells .

• Appearance: Firm, round nodules; can vary in size and sometimes emit a foul odor, especially if infected.
• Treatment: Most resolve on their own, but persistent, growing, or infected cysts should be evaluated by a veterinarian.

Dermoid Cysts

Dermoid cysts are congenital (present from birth) and contain a mix of skin, hair follicles, and sometimes other tissues. They are relatively rare in dogs but can occur in certain breeds.

• Appearance: Hairy, round mass beneath the skin, usually on the back or midline.
• Treatment: Typically requires surgical removal due to risk of infection and ongoing irritation.

Other Types of Cysts

• Pilar (Trichilemmal) Cysts: Arise from the outer root sheath of hair follicles. Often found on the head or neck; hard in texture.
• Apocrine Gland (Sweat Gland) Cysts: Appear near the anus or groin, sometimes secrete fluid; often benign.
• Interdigital Cysts: Develop between the toes, typically due to trauma or infection. May be painful and ooze blood or pus.
• Ovarian and Kidney Cysts: Internal cysts that can sometimes disrupt organ function; require veterinary assessment.

What Causes Cysts in Dogs?

The development of cysts in dogs usually stems from clogged glands, injury, infection, genetics, or (less commonly) underlying medical conditions. Factors include:

• Blocked Sebaceous or Sweat Glands: Leading to buildup and cyst formation.
• Hair Follicle Inflammation: Initiates follicular/epidermoid cysts.
• Genetic Predisposition: Some breeds are more prone.
• Injury or Trauma: Can result in false cysts.
• Congenital Factors: Dermoid cysts are present from birth.

When to Worry: Signs a Cyst Needs Veterinary Attention

While most cysts are harmless, certain symptoms suggest a need for prompt veterinary evaluation:

• Rapid growth or change in appearance
• Bleeding, ulceration, or recurring rupture
• Redness, heat, swelling, or signs of pain/infection
• Persistent discharge or pus
• Interference with movement or normal activities

Sometimes, what appears to be a cyst could be a skin tumor or even cancerous growth. A veterinarian may perform a fine needle aspirate, biopsy, or surgical excision for diagnosis.

Diagnosing Cysts in Dogs

Proper diagnosis is essential to distinguish benign cysts from other, more serious masses. Diagnosis may involve:

• Physical Examination: Assess shape, texture, and location.
• Fine Needle Aspiration (FNA): A sample of the cyst’s contents is examined under a microscope.
• Biopsy or Removal: Entire cyst is surgically removed and sent for histopathology, especially if malignancy is suspected.

Treatment and Management of Cysts

Treatment varies according to the type, location, size, and cause of the cyst:

• Leave it alone: Many small, benign, or false cysts heal without intervention.
• Medical Management: If the cyst becomes inflamed or infected, antibiotics or anti-inflammatories may be prescribed.
• Surgical Removal: Recommended for recurring, persistent, or bothersome cysts. For true cysts, the lining must be completely removed to prevent recurrence .
• Do Not Squeeze or Pop: Attempting to drain cysts at home increases risk of infection and complications.

Can Cysts Be Prevented?

While not all cysts can be prevented, some steps may lower your dog’s risk:

• Maintain regular grooming and cleanliness to help prevent clogged hair follicles.
• Feed a balanced diet to support skin health.
• Regular veterinary checkups for early detection.

Frequently Asked Questions (FAQs) About Cysts on Dogs

Q: Should I be worried if my dog has a lump?

A: Not all lumps are dangerous, but it’s important to have new or changing lumps checked by a vet for proper diagnosis and peace of mind.

Q: Can I pop or drain a cyst on my dog at home?

A: No. Popping or squeezing a cyst at home can cause pain, infection, or further complications. Uneven removal may also result in recurrence. Always seek veterinary care for any irritating or persistent cysts.

Q: Are cysts on dogs contagious?

A: No. Cysts are not infectious and cannot be transmitted from one dog to another .

Q: What is the difference between a cyst and a tumor?

A: Cysts are usually benign, fluid- or semi-solid-filled sacs, while tumors can be benign or malignant and often originate from uncontrolled cell growth. Only a veterinary exam can reliably tell the difference.

Q: Will a cyst go away on its own?

A: Many false cysts and some small follicular/sebaceous cysts may resolve without intervention. Those that grow, rupture, or become infected should be evaluated and possibly removed by a vet.

Key Takeaways for Dog Owners

• Monitor all lumps and bumps, noting any changes.
• Most canine cysts are benign, but prompt veterinary examination is recommended for new, changing, or persistent lumps.
• Do not squeeze or attempt home removal of cysts.
• Surgical removal is sometimes necessary, especially for recurring or problematic cysts.

Your veterinarian is your best resource for questions and treatment options regarding cysts on your dog. With vigilance and proactive care, most canine cysts can be managed safely.

Author

Shinta

 

Shinta is a biotechnologist turned writer. She holds a master's degree in Biotechnology from Karunya Institute of Technology and Sciences and a PG Diploma in cellular and molecular diagnostics from Manipal University. Shinta realised her love for content while working as an editor for a scientific journal.

Read full bio of Shinta